Graphic issues on Macbook Pro ? 8.1.5

[braincell]

hi there
since 8.1.5 i have the issue that my screen freezes somehow, after some time..
it takes about 10-20sec that my screen is showing what i am doing, like a big latency.
had this also one time with a customer,and after reinstalling live it was ok, but not on my mac now...
any help ?

[braincell]

hi , again me...some additional info...
i just turned my graphic card (energy settings in system preferences) to high performance, and the issue seems to be gone for now.
can anybody reproduce this issue ?
greetz
ralph